The present invention relates to a transmission format, a communication control apparatus and method, a recording medium, and a program. More specifically, the present invention relates to a transmission format in which JPEG-2000 data can be transmitted through the Internet, a communication control apparatus and method, a recording medium, and a program.
When streaming is performed on the Internet, problems, such as deterioration of data due to packet loss or delay of arrival, may be caused. In an encoding method using interframe differential, such as moving picture experts group (MPEG) format and H.26x system, when data of a frame is lost due to a packet loss, the error is propagated. That is, the image quality of the subsequent frames is badly affected. Also, in the MPEG method, a compression rate is increased by motion prediction. However, by performing motion prediction, an algorithm becomes complicated and the processing time increases in proportion with the square of the frame size. Accordingly, a several-frame encoding delay occurs in principle. When interactive real-time communication is performed, this delay is barely within the tolerable delay time of 250 ms, which cannot be ignored.
On the other hand, in Motion JPEG 2000, static image compression algorithm JPEG2000, which is the successor of joint photographic expert group (JPEG) is continuously played back so as to generate a motion picture. The file format of the Motion JPEG 2000 is defined in part 3 of the JPEG-2000 standard which is standardized by ISO. Since the Motion JPEG 2000 is a motion picture format which does not use interframe differential, the above-described problems do not occur. Also, in the JPEG 2000 which is the basic of the Motion JPEG 2000, the compression rate is increased by a wavelet transform and entropy encoding. Thus, in the JPEG 2000, higher compression and higher definition can be achieved compared to the Motion JPEG and a DV, which are the same as the JPEG 2000 in that they are motion picture formats which do not use interframe differential. Also, the JPEG 2000 has an error tolerance. Accordingly, a motion picture format such as the Motion JPEG 2000, which does not use interframe differential, is suitable for the environment where packet loss occurs, such as the Internet.
However, the transmission format for performing streaming using JPEG 2000 does not exist. The Motion JPEG 2000 defined in part 3 of JPEG 2000 includes only a saving method, that is, a file format. In many cases, a realtime transport protocol (RTP) is used to transfer real-time media over the Internet. However, even the IETF, which is considered a format for transferring various media with the RTP, does not define the RTP format for JPEG 2000.